<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div class="container">
      <div class="content">
        <div class="phone">
          <img
            src="https://element.eleme.io/static/theme-index-blue.c38b733.png"
            width="100%"
            height="100%"
          />
          <div class="jumbotron-red">
            <img
              src="https://element.eleme.io/static/theme-index-red.c8e136e.png"
            />
          </div>
        </div>
      </div>
    </div>
    <script>
        window.addEventListener("scroll",this.handleScroll)
        function handleScroll() {
            let scrollTop = window.scrollY;
            let jumbotron = document.querySelector(".jumbotron-red");
            jumbotron.style.height = scrollTop + "px"
        }

    </script>

    <style>
        .content {
            height: 2000px;
            width: 98vw;
            overflow: hidden;
            box-sizing: border-box;
        }

        .phone {
            position: relative;
            height: 440px;
            width: 740px;
            margin: 80px auto;
        }

    .jumbotron-red {
        position: absolute;
        top: 0;
        left: 0;
        height: 0;
        overflow: hidden;
    }       
    
    .jumbotron-red img {
        width: 740px;
        height: 440px;
    }

    </style>
  </body>
</html>
